During rehabilitation patients are often asked by their physicians to apply a specific amount of weight on a body part, for example, during recuperation following a full knee replacement. While total isolation of the leg may be unnecessary, the leg may not be strong enough to support the full body weight of the person. As a result, the doctor will typically instruct the patient to apply 40%, for example, of his full weight upon the leg. This scenario is also common among other medical treatments such as full or partial hip replacements, healing of broken bones, pulled muscles, etc. In some cases, applied pressure is required for proper healing. For example, medical testing has shown that broken bones heal best along stress lines. Thus, the application of pressure to an injured limb often enhances its recovery.
The amount of force applied to the injured limb is significant because too much force can aggravate injuries, but too little force will not promote healing. For example, if a person is recuperating from a pulled muscle, some force is desired, but if the muscle is not fully recovered, too much pressure can cause re-injury of the muscle. Conversely, if a broken bone is to heal properly, force must be applied to the limb. If too little force is applied, fusion of the bone fragments may not occur and proper healing will take longer than necessary. The patient must apply enough force to aid the healing process, while taking precautions to prevent further damage.
The problem arises in that patients can not always accurately determine how much weight they are applying to their leg. Common practice has been to have the patient stand on a scale and place, for example, thirty pounds on the leg to see how it feels. The patient is then asked to reproduce that feeling with every step, a practically impossible task. A system is required that can sense the amount of weight being applied and then inform the patient when the proper level has been reached.
Prior systems have been developed that study pressure exerted by the foot. Most notably, a system called "Emed" was developed by Novel Electronics Inc. of Minneapolis, Minn. This system requires the patient to walk across an electronic pad, which senses the pressure applied at various points and conveys that information to a computer. Emed is usually operated by a medical practitioner in a doctor's office where it provides complex and detailed stress analysis data. Emed can not be operated by the patient and only returns data from a single step. It is not portable and can not be used during daily walking. A system for promoting the healing of the aforementioned injuries should be able to convey, directly to the patient, information regarding the amount of weight being supported by a limb during every step.
Accordingly, it is an object of the present invention to provide a device that will sense the amount of force being applied upon a leg by every step taken.
It is a further object of the invention to provide a device that will convey a signal to the user when the desired amount of force has been applied to the leg.
It is another object of the present invention to provide a device that will produce an output signal whenever a pre-selected force has been applied such that this output signal can be recorded for future analysis thereof.
Another object of the present invention is to provide a device that will transmit signals relating to the force being applied to a foot such that the same can be recorded at a remote location for analyzing the degree of recovery of a patient, for example.
Further, it is an object of the present invention to provide a shoe-like structure in which is mounted a force sensitive element such that an electrical signal is produced that is related to the amount of force being applied thereto.
A further object of the present invention is to convey to the user a plurality of signals, one of which indicates when the amount of the preselected force has been applied, and at least one at a lesser force.
These and other objects of the present invention will become apparent upon the consideration of the following description with reference to the drawings referred to therein.